Turbine-blade attachment



PARSONS; S. S. COOK AND A. P. BENNETT.

TURBINE BLADE ATTACHMENT.

APPLICATION FILED FEB. 4.1919. 1,328,640.

Patented Jan. 20, 1920.

. AB C D Egfi Fig.2

lmvea/omsz- Char/es A/ge/wm Paw-mas,

Sfan/ey Saw/2% Coo/F, i

A/mr 1 /7/1450 6e ne f, hzmzwwm PATENT oFFIG CHAR-LES ALGERNON PARSONS,

STANLEY SMITH 000K,

AND aivnnnw rnrnr BENNETT,

TO SAID PARSONS.

'IURIBIliE-BLADE ATTACHMENT.

Specification of Letters Patent.

Patented Jan. 720, 1920.

Application filed February a, 1919. Serial No. 274,942.

To all whom it may concern:

Be it known that we, CHARLES Anennnon lARsoNs, STANLEY SMITH Coon, and AN- nnnw PHIL? BENNETT, all subjects of the King of Great Britain, residing at Heaton lVo'rks, Newcastle-upon-Tyne, in the county of Northumberland, England, have invented certain new and useful Improved Turbine- Blade Attachments, of which the following is a specification.

The present invention relates to means for.

securing the last blade of a row of turbine blades which are undercut to fit circumferential projections on the sides of the retainingp grooves, and is particularly applicable to, constructions in which a blade is integral with or attached to a packing or spacing section.

It is usual in such constructions to provide a local recess in the side of the groove in the blade carrier to allow the blades and spacing sections to be inserted, this recess being subsequently filled by a closing piece or pieces, so asto ret in the blades and sections opposite the recess. It is ditllcult to obtain positive attachment to the blade carrier of the closing piece, or of the last inserted closing piece, as it must be inserted radially and secured by screws, or by calking or similar means. It is therefore desirable when the blade carrier is the rotor that the last inserted closing piece shall not be subject to, or shall only be subject to a small proportion of, the radial forces tending to extract the blades and sections, as thereby the advantages of thepositive attachment of the latter to the groove would be lost, so far as the blades, &c., opposite the recess are concerned.

In order to obviate this disadvantage, it has been proposed to make the cross-section of the-recess (in a plane parallel to the vgroove sides) such that cut, and to provide a locking piece of the same cross-section but of less width than the recess, so t at the locking piece can slide toward and away from the groove. The locking piece is slid away from the groove until the blades and sections are all inserted, after which it is slid into contact with the-latter, being so shaped that it registers with the circumferential projections, serrations, &c., in the blades and spacing sections. The recess is then filled with a filling or closing piece, and a positive while itself is held the sides are underhold of the blades to the rotor is thus obtained.

With such constructions, however, the width of the recess (measured perpendicular to the sides of the groove) is great, thus tending to weaken the rotor, and there is great difficulty in machining the undercut sides of the recess, due principally to its having only one open end.

The object of the present invention is to provide a construction in which the blades and spacing sections in a groove are all positively retained against their radial extracting forces without the above mentioned disadvantages.

The invention consists .in'making the locking piece and the recess in which it is inserted of such circumferential length that it overlaps three or more separate blades and packing sections, and inserting it after the last inserted section and holding it in such a manner that it holds the last inserted section positively in the radial direction positively in the radial direction by the adjacent sections, these being held positively in the radial direction by the circumferential groove in which the blades are inserted.

The invention further consists in making the circumferential length of the recess substantially a multiple of the circumferential pitch of the packing sections, in arranging the latter so that each end of the recess occurs substantially opposite the center of circumferential length of the opposing face of a packing section. and in providing a locking piece of substantially the same length as, but of less thickness than, the recess, one side of this locking piece registering with the serrations or projections of the packing sections, the other side forming contact with a closing piece or pieces which preferably are calked .in t fill up the recess and prevent the locking piece from coming out of register with the packing sections.

The invention further consists in the improved means for attaching turbine blades hereinafter described.

Referring to the accompanying. drawings:

Figure 1 is a plan view, and

Fig. 1 is a detail perspective View of a part of the blade carrier showing the groove, the recess and locking means.

Fig. 2 1s a sectional elevation of a portion the 7 are sectional views being inserted so that the -middle of each spacing section or packing piece of blades E, F, is opposite the adjacent end of the piece A. The recess G, which accommodates the locking piece A, is of substantially the same length. as, but wider than, the piece A, the face opposite the groove H being under cut. -The locking piece A is held in contact with the blades E, G, F by two filling pieces 13,1), of brass, copper, or other suitable material, which are calked in position, the face of the locking piece on which they bear being serrated as shown, or smooth.

- The face of the locking piece A. which engages the blades and their packing piece, has or may have the same configuration as the wall of the groove in which the blades and their packing pieces are located. When it is in position, therefore, it forms acontinuation of the groove, presenting the same characteristics as the wall. As this locking pieceis longer than the width of a packing piece, its ends overlap and lie opposite the adjacent packing pieces, preferably terminating at about the centers of these pieces. These adjacent pieces are, however, engaged by and interlock with the wall of t 1e groove for apart of their length. They, therefore, are positively held by the wall of the groove and they also positively hold the locking piece. The locking iece in turn positively holds the packing piece of the blade which is between the overlapped packing pieces.

Referring specifically to Fig. l, the locking piece is longer than the packing piece G, and, therefore, overlaps on the packing ieces E and F. The packing pieces E and however, engage the integral ribs on the walls of the groove, sothat they are positivelyheld by this engagement. As the lockingpiece positively engages these positively held 'pieces,.it in turn is held against radial displacement by them, and since it engages the intermediate packing piece G, it

holdsthe intermediate packing piece from displacement.

As shown in Fi 3, the locking piece A. may be formed wit a number of projections J for use in connection with blading' in which this formof retaining device is used. In the modification illustrated in Fig.

' Three filling pieces B, D, K

blades preferably made integral with the spacing sections or packing pieces,

the recess C, instead of being undercut, is serrated on the face opposite the groove H. also are used, the bottom one being of steel so as to offer a large resistance to compression consequent on transverse bending forces on the blades.

Azs'show'n in Fig. 5 the projections on the side of the groove and on the locking piece are perpendicular to the plane of the groove, so that radial-blade-extracting forces will not have components in the longitudinal direction, tending to compress the calking or closing pieces.

It will be seen with this construction that so far as radial extracting forces are concerned, each of the blades br sections is positively attached to the rotor. The sections in the groove opposite the ends of the repiece arepositively held by cess and looking on the sides of the grQ Ve the projections formed on the body of the rotor. ing piece is held y these two sections inthe radial' direction, also positively, while the last inserted sectionopposite the center of locking piece is positively held by the pro jection on the lockihg piece, this locking piece, as above stated, being also positively held. The whole of the sections are held positively by the projections of the groove on the side opposite the recess. It will be seen, therefore, that the c'alking or closing pieces are not subjected to the blade extraction forces, their only function being to hold the locking piece in register with the sections op osite to it. 4

it will further be seen that the locking piece is, through its registration with the packing sections, subjected to forces in opposite directions, the sections at the ends of the recess tending to retain it against the outward radial tions wholly within the recess.

In themodifications shown in Figs. 16 and 7 the face of the recess C opposite the groove is undercut and preferably serrated, and the face of the locking piece A, which forms con The lockforces of the section or sectact with the closing pieces-is similarly inclined to the plane of thegroove. With this constructibn it will be seen that the tightly calked closing pieces B, D and K, will assist to some extend'in resisting the radial extracting forces on the locking piece and the blades and sections with which. it is in register. This construction may be employed where it is desired, to have a short recess, as shown in Fig. 8.

Tn cases where the shape of the sections is such that the last one cannot be inserted from the side, but must be inserted radially, recesses, &c., may be provided at each side of the groove. Each of these two-recesses would be provided with a locking piece and closing pieces as described above. A's-an alternatlve employing one recess only, part'of the last section may be removed to allow it to.

' locking piece in desired be made integral with recess spans a packing neeaeao be inserted from the side, and a fillingnp piece used to fill the groove before the locking piece is introduced. This virtually results in making the last inserted section in two pieces, but the filling up piece may it T the locking piece,

It will be seen that the invention has special advantages in cases Where the blades and spacing sections are integral, or are permanently attached to each other before assembling in the rotor groove, as it does not prevent such combination of the lastinserted blade and "section and at the same time provides a positive attachment to the rotor of all the blades and sections.

Having now particularly described and ascertained the nature of our said invention and in What manner the sarne is to hope!- formed, yve declare-that What We claim is 1. In a turbine a blade carrier having a groove, blades and packing pieces located in the groove, a "recess in a wall of the groove which is bircumi'ei'entially longer than a packing piece or pieces and so related to the blades and packing pieces that when they are inserted in the groove the piece or pieces and its ends lie opposite other packing pieces, a locking piece located in the recess and spanning a packing piece or pieces, the ends of said lockingi'piece overlapping the other packing "pieces, interengaging projections on the Walls or the groove, the packing pieces and locking piece, whereby the overlapped packing pieces positively lock the locking piece, the spanned packin piece or pieces, and means for holding the locking piece in the recess.

2. In a turbine a blade carrier having a groove, blades and packing pieces located in the groove, a recess in a Wall of the groove which is circnmferentiallv packing piece or ieces an so related to the blades and packing pieces that whenthey are inserted in the groove it spans a packing piece or pieces'and its ends lie opposite other packing pieces, a in the recess and spanning a packing piece or pieces, the ends of said locking piece overlapping the other packing pieces,interengaging projections on th the packing pieces and the locking piece, whereby the overlapped acking pieces positively lock the locking piece, and the locking piece positively locks the spanned packing piece or pieces, and calking for holding the the recess. 3. In a turbine a. blade carrier having a groove, blades and packing pieces located in the groove, a recess in a wall of the groove which is circumferentially longer than a packing piece or pieces and so related to the blades and packing pieces that and the locking piecepositiveiy locks longer than a locking piece-locatede walls of the gropve,

- posite other packing when they are inserted in the groove the recess spans a packing piece or ends lie opposite other packing pieces, a locking-piece located in the recess and spanhing a packing piece or pieces, the ends of said locking piece overlapping the other packing pieces, interengaging projections on the Walls of the groove, the packing pieces and the locking piece, whereby the overlapping packing pieces positively lock the locking piece, and the locking piece positively locks the spanned packing piece or pieces, and calking blocks for holding the locking piece in the recess, the inner one 0' said blocks being of steel.

4:. in a turbin 21- blade carrier having a groove, blades and packing pieces located in the groove, a recess in a wall of the groove which is circuniferentially longer than a packing piece or pieces and so related to the blades and packing pieces that when they are inserted in the groove the recess spans a packing piece or pieces and its ends he opposite other packing pieces, the face of the recess opposite the packing pieces being undercut, a locking piece located in the recess and spanning a packing piece or pieces, the ends of said locking piece'overlapping the other packing pieces, interengaging projections on the Walls of the groove, the packing pieces and the locking piece, whereby the overlapped packing pieces positively lock the locking piece and the locking piece positively locks the spanned packing piece or pieces, and calking for holding the locking piece in the recess.

5. Ina turbine a blade carrier having a groove, blades and packing pieces located in the groove, a recess in a Wall of the groove which is circuinterentially longer than a packing piece or pieces and so related to the blades and packing pieces that when they are inserted in the groove the recess spans a packin piece or pieces and its ends lie opposite other packing pieces, a locking piece located in the recess and spanning a packing piece or pieces, the ends of said locking piece overlapping the other packing pieces, interengaging projections on the Walls of the groove, the packing pieces and the locking piece, said projections havin two surfaces which are oppositely inclined to the plane of the groove side, and-'means for holding the locking piece in t e recess. 1

-6. In a turbine, a blade carrier having a roove, blades and packing pieces located in the groove, a recess ina wall of the groove which 's circumferentiallv longerthan a packing piece or. pieces an blades and packing pieces are inserted in the packing piece or that when they woes and its ends he oppieces, a locking piece located in the recess and; spanning a packpieces and its groove the recess spans a s0 related to the i ing piece or pieces, the ends of said locking piece overlapping the other packing pieces, interengaging projections on the Wall of the groove, the packing pieces and the look ing piece, said projections having two surfaces Which are oppositely inclifiedjto the plane of the groove side, and calking blocks for holding the locking piece in the "recess.

In a turbine a blade carrier having a groove, blades and packing pieces located in the groove, a recess in a wall of the groove which is circumferentially longer than a packing piece, said recess terminating substantially opposite the center of the ad acent packing pieces, a locking piece located in therecess, said locking piece spanning a packing piece and having its ends terminating substantially opposite the centers of the packing pieces adjacent to the spanned packing piece, interengaging pro- Jections on the Walls of the groove, the

packing pieces and the locking piece, whereby the overlapped packing pieces positively lock the locking piece and the looking piece positively locks the spanned packing piece, and means for holding the looking piece in the recess.

8. In a turbine a blade carrier having a groove, blades and packing pieces located in the groove, a recess 1n a Wall of the groove which is circumferentially longer than. a packing piece, said recess terminating substantially opposite the center of the adjacent packing pieces, a locking piece located in the recess, said locking piece spanning a packing piece and having its ends terminating substantially opposite the "centers of the packing pieces adjacent to the saaeao spanned packing piece, interengaging projections on the Walls of the groove, the packing pieces and the locking piece, whereby the overlapped packing pieces positively lock the locking piece and the locking piece positively locks the spanned packing piece, and calking blocks for holding the locking piece in the recess.

9. In a turbine a blade carrier having a groove, blades and packing pieces located in the groove, a recess in the Wall of the groove which is circumferentially longei than a packing piece or pieces and is so related to the blades and packing pieces that when they are inserted in the groove the recess spans a packing piece or pieces and its ends lie opposite other packing pieces, a locking piece located in the recess and spanning the packing piece or pieces, the ends of said locking piece overlapping the other packing pieces, interengaging projections on the Walls of the grooves, the packing pieces and locking piece, and means between the locking piece and the face of the IGCQSSOPPOSItQ the packing pieces for pressing the locking piece into engagement with the packin pieces, the recess being of such a lengt circumferentially as to permit the radial entrance of the locking piece into the recess at a point close up to the packing pieces, substantially as described.

In testimony whereof we have signed our names to this specification.

CHARLES ALGERNON PARSONS, STANLEY SMITH 000K. ANDREW PHILP BENNETT, 

